This invention relates to apparatus for marking the radial first harmonic high point on a tire which may be defined as the highest area of force on a once-per-revolution force curve of a tire.
As is well known in the art to which my invention relates, a tire is an assembly of many components which may individually or collectively create a high force area which may be felt in a vehicle, such as an automobile. This high force area is determined and identified by the uniformity machine in a conventional manner. Heretofore, the high force area has been marked by spraying a marking fluid, such as ink, onto the tire as it rotates on the uniformity machine. This high point mark is then used in a rim-tire match mounting operation so that the assembly produces the best combination of ride characteristics when the tire is mounted on a vehicle, such as an automobile. That is, the high point mark on the tire is matched with the low point on the rim, which is usually identified by the location of the valve stem opening in the rim. Accordingly, by this match mounting operation, better concentricity is obtained.
Difficulties have been encountered with prior methods of marking the radial first harmonic high point on tires due to the fact that the spray apparatus heretofore employed does not produce a clear predictable mark which is neat in appearance. That is, where the marking fluid, such as point or ink is thrown onto the tire by spray apparatus, the marking fluid is spattered onto the tire in such a manner that a clear mark is not obtained. Such spray apparatus for applying the marking fluid is also very difficult to maintain in satisfactory working order due to the fact that the spray apparatus soon becomes clogged and must be disassembled for cleaning.